Geometry for low-inertia aerosol capture: Lessons from fog-basking beetles.

Water in the form of windborne fog droplets supports life in many coastal arid regions, where natural selection has driven nontrivial physical adaptation toward its separation and collection. For two species of Namib desert beetle whose body geometry makes for a poor filter, subtle modifications in shape and texture have been previously associated with improved performance by facilitating water drainage from its collecting surface. However, little is known about the relevance of these modifications to the flow physics that underlies droplets' impaction in the first place. We find, through coupled experiments and simulations, that such alterations can produce large relative gains in water collection by encouraging droplets to "slip" toward targets at the millimetric scale, and by disrupting boundary and lubrication layer effects at the microscopic scale. Our results offer a lesson in biological fog collection and design principles for controlling particle separation beyond the specific case of fog-basking beetles.

Comparative Material and Mechanical Properties among Cicada Mouthparts: Cuticle Enhanced with Inorganic Elements Facilitates Piercing through Woody Stems for Feeding.

Adult cicadas pierce woody stems with their mouthparts to feed on xylem, suggesting the presence of cuticular adaptations that could increase hardness and elastic modulus. We tested the following hypotheses: (a) the mouthpart cuticle includes inorganic elements, which augment the mechanical properties; (b) these elements are abundant in specific mouthpart structures and regions responsible for piercing wood; (c) there are correlations among elements, which could provide insights into patterns of element colocalization. We used scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) to investigate mouthpart morphology and quantify the elemental composition of the cuticle among four cicada species, including periodical cicadas (Magicicada sp.). Nanoindentation was used to quantify hardness and elastic modulus of the mandibles. We found 12 inorganic elements, including colocalized manganese and zinc in the distal regions of the mandible, the structure most responsible for piercing through wood; nanoindentation determined that these regions were also significantly harder and had higher elastic modulus than other regions. Manganese and zinc abundance relates to increased hardness and stiffness as in the cuticle of other invertebrates; however, this is one of the first reports of cuticular metals among insects with piercing-sucking mouthparts (>100,000 described species). The present investigation provides insight into the feeding mechanism of cicadas, an important but understudied component of their life traits.

Nanoconfined Crystallization in Poly(lactic acid) (PLA) and Poly(ethylene terephthalate) (PET) Induced by Various Forms of Premelt-Deformation.

The processing-structure-property relationship using poly(lactic acid) (PLA) and poly(ethylene terephthalate) (PET) is explored. Specifically, both pre-extension and preshear of amorphous PLA and PET above their glass transition temperatures Tg , carried out in the affine deformation limit, can induce a specific type of cold crystallization during annealing, i.e., nanoconfined crystallization (NCC) where crystal sizes are limited to a nanoscopic scale in all dimensions so as to render the processed PLA and PET optically transparent. The new polymer structure after premelt deformation can show considerably enhanced mechanical properties. For example, premelt stretching produces geometric condensation of the chain network. This structural alternation can profoundly change the mechanical characteristics, e.g., turning brittle PLA ductile. In contrast, after preshear of amorphous PLA above Tg , the NCC containing PLA remains brittle, showing the importance to have geometric condensation from processing. Both AFM imaging and SAXS measurements are performed to verify that premelt deformation of PLA and PET indeed results in NCC from annealing that permits the strain-induced cold crystallization to take place on the length scale of the mesh size of the deformed chain network.

Material Properties and Morphology of Prestomal Teeth in Relation to the Feeding Habits of Diptera (Brachycera).

Prestomal teeth are cuticular projections on the mouthparts of some fly species that rasp surfaces when feeding. Although prestomal teeth morphology has been reported for several fly species, their material properties have not been investigated. Here we report the morphology, elemental composition, extent of sclerotization, hardness, and elastic modulus of prestomal teeth and relate these findings to feeding habits. Scanning electron microscopy revealed that species categorized as flower visitors have a large labellum with numerous pseudotracheae and lack prestomal teeth, generalist species have these same features but with prestomal teeth, and specialist species that feed on blood or other insects have a smaller labellum with few or no pseudotracheae and relatively large prestomal teeth. Confocal microscopy revealed that prestomal teeth are heavily sclerotized and the labellum contains resilin, an elastomeric protein. Hardness and elastic modulus were explored with nanoindentation and showed that the insectivorous Scathophaga stercoraria had the hardest prestomal teeth and the highest modulus. Energy dispersive x-ray spectroscopy revealed that prestomal teeth had low concentrations of inorganic elements, suggesting that hardness might be partially supplemented by inorganic elements. Our findings indicate that prestomal teeth morphology and material properties relate more to feeding habits than to phylogeny.

An open-source dual-beam spectrophotometer for citizen-science-based water quality monitoring.

Efforts to understand and mediate threats to water supplies rely on collection of reliable data at large scale, a goal which is often limited by availability of tools that are both affordable and reliable. We present here a low-cost, easy-to-use, do-it-yourself (DIY) spectrometer for measurement of a variety of relevant solute concentrations when coupled with inexpensive commercially-available reagents. Comparison of its performance with commercial options demonstrates the potential value of this device as transparent, versatile, and accurate-enough alternative for widespread application.

[Comparisons of Clinical Effectiveness and Survival between Continuous and Interrupted Chest Compressions in Out-of-hospital Cardiac Arrest].

Objective To compare the clinical outcomes of continuous chest compressions (CCP) or interrupt chest compression (ICP) for the cardiac arrest patients. Methods Totally 114 adult patients with out-of-hospital non-trauma-related cardiac arrest that needed cardiopulmonary resuscitation (CPR) in Quzhou People's Hospital from January 2014 to January 2017 were enrolled in this study. Patients who divided into CCP group (n=70) and ICP group (n=44) according to the maneuvers. The clinical data of these two groups were collected and compared. Results The chest-compression fraction was higher in CCP group than in ICP group (0.85±0.05 vs. 0.75±0.06,t=9.868,P=0.000),and the rate of chest-compression pause per minute was significantly lower in CCP group (3.5±1.6 vs. 6.9±3.8,t=-10.669,P=0.000). The interval from arrival at a first aid location to CPR,duration of CPR,electric defibrillation frequency,airway establishment,intubation time,and use of first-aid drugs were not statistically significant (all P>0.05). Significantly lower proportion of patients in CCP group were transported to a hospital (42.8% vs. 56.8%,Χ2=0.198,P=0.032). The proportion of patients achieving recovery of spontaneous circulation (ROSC) in CCP group were significantly lower than in ICP group (28.5% vs.47.7%,Χ2=0.191,P=0.038). The proportion of patients who got successful resuscitation in CCP group was significantly lower than in ICP group (20.0% vs. 38.6%,Χ2=4.470,P=0.029). The proportion of patients who survived and were discharged was significantly lower in CCP group than in ICP group (8.6% vs.22.7%,Χ2=0.487,P=0.041). There was no significant difference between these two groups in ROSC time,proportion of survivors one month after discharge,proportion of survivors six months after discharges,and neurological outcomes (all P>0.05). Among the survivors,2 patients had ST-elevation myocardial infarction,1 had rheumatic heart disease,2 had non-ST segment elevations myocardial infarction,and 1 had dilated cardiomyopathy. Multivariate Cox proportional hazard regression analysis was used to analyze the independent factor of prognosis. The time from cardiac arrest to CPR (HR=1.047,95% CI=1.003-1.093,P=0.034),the time from CPR to ROSC (HR=1.021,95% CI=1.003-1.038,P=0.020),and Glasgow Coma Scale (GCS) 1 score (HR=1.551,95% CI=1.022-2.355,P=0.039) were the independent risk factor for deaths within 180 days after discharge. Conclusion Long interval from cardiac arrest to CPR,long interval from CPR to ROSC,and a Glasgow Coma Scale score of>1 are the independent risk factors of deaths within 180 days after discharge. Therefore,the survival outcomes of CCP may not be superior to ICP in patients with out-of-hospital cardiac arrest.

Broadband angular filtering with a volume Bragg grating and a surface grating pair.

We propose and perform broadband angular filtering with the combination of a volume Bragg grating and a surface grating pair. The condition for broadband operation is discussed. Near-field modulation, contrast ratio, and power spectral density are used to evaluate the filtering performances in the spatial and frequency domain. Experimental results show that the bandwidth of the output beam through the grating combination is remarkably increased, and the medium and high frequencies are effectively eliminated.

Diffraction of volume Bragg gratings under high flux laser irradiation.

Diffraction property of transmitting volume Bragg gratings (VBGs) recorded in photo-thermo-refractive glass (PTR) is studied under the irradiation of a continuous-wave fiber laser with flux of 1274 W/cm2. Dependence of temperature characteristics of VBGs prepared by different crystallization temperatures is presented. When temperature of VBGs rises up to 33°C, there are a 2.7% reduction and 1.59% ripple of diffraction efficiency for VBGs. The period variation caused by the thermal expansion of VBGs is used to explain the reduction of diffraction efficiency, and experimental results are in agreement with theoretical analysis.

Optimization of spatial filter with volume Bragg gratings in photo-thermo-refractive glass.

We present a method for optimizing spatial filter performance by inserting volume Bragg gratings (VBGs) in front of the traditional spatial filters. The experimental results show that the cutoff frequency is modified with the insertion of VBGs. We also demonstrate the optimization of filtering performance in both the spatial and frequency domains, with detailed comparison of near-field modulation, contrast ratio, and power spectral density of output laser beams.

One-way wicking in open micro-channels controlled by channel topography.

One-way wicking (microfluidic diode) behaviors of a range of IPA-water mixtures on internally structured PDMS-based open micro-channels were experimentally demonstrated and quantified. The open microfluidic channels, each internally decorated with an array of angled fin-like-structure pairs, were fabricated using a combined photolithography and soft molding procedure. Propagations of wetting fluids were found to be much more impeded on the fin-tilting direction, or the hard wicking direction, comparing to the opposite direction, or the easy wicking direction. This asymmetric wicking behaviors were attributed to the structure-induced direction-dependent Laplace pressure. Two key parameters - the contact angle of the wicking fluid and the tilting angle of the fin-like structures - were studied. The effects of preferential evaporation and wetting instability were also investigated. The findings of this study are expected to provide a better understanding of how fluids interact with micro-scaled structures and to offer a new way of manipulating fluids at the micron and nanometer scales.

Two-dimensional angular filtering by volume Bragg gratings in photothermorefractive glass.

We propose and perform two-dimensional angular filtering on the basis of volume Bragg gratings (VBGs) in a series connection for cleaning up a laser beam. The dependence between angular selectivity and VBG parameters is analyzed with the coupled wave theory. Near-field modulation, contrast ratio, and power spectral density were used to evaluate the effect of filtering in both the spatial and frequency domain. The results from our initial experiments showed that the near-field modulation and contrast ratio of laser beam were remarkably improved.

Simulations of novel nanostructures formed by capillary effects in lithography.

High aspect ratio three-dimensional nanostructures are of tremendous interest to a wide range of fields such as photonics, plasmonics, fluid mechanics, and biology. Recent developments in capillary force lithography (CFL) have focused on taking advantage of the formation of menisci to enhance the functionality of small size-scale structures. In this study, simulations of the three-dimensional shapes of equilibrium menisci formed in capillaries with various cross-section geometries are studied. The capillary cross sections include regular polygons and equilateral star-shapes with sharp and rounded corners. The characteristic dimension of the physical lithography systems which are simulated is on the order of 100nm. At such size-scale, surface-tension-effects are predominant, and as a consequence, our simulations demonstrate that nanometer-sized structures with great application potentials can be fabricated. Specifically, this study demonstrates that surfaces with three-dimensional nanoscale structures can be fabricated from templates with micron or sub-micron features through the development of cusps in the corners of the polygonal capillaries. Quantitatively, the effects of contact angle, corner angle, meniscus confinement, and corner rounding radius are examined and scaling analyses are presented to describe the dependencies of the height variation across the meniscus on these parameters. These simulations serve as useful guides for extending the development and implementation of capillary force lithography.

[Variants of exon 4 and its flanking region of LPL Gene in patients with hyperlipidemia].

To elucidate abnormalities of LPL gene in hyperlipidemia in the Chinese population in Guangdong,genomic DNA was extracted from leukocyte of 258 patients with primary hyperlipidemia.A segment of LPL gene including exon 4 and its flanking sequences was analyzed by PCR-SSCP. The PCR products with abnormal SSCP pattern were cloned and sequenced. As a C-->T transition mutation at-6 bp of intron 3 was found in two Chinese with hyperlipidemia and the mutation was not found in 252 normolipidemic controls,the C-->T transition in intron 3 may be related to hyperlipedemia.